Quicktime File Format (2012-08-14).pdf

Movie AtomsOverview of Movie AtomsFlagsThree bytes of space for future movie header flags.Creation timeA 32-bit integer that specifies the calendar date and time (in seconds since midnight, January 1, 1904)when the movie atom was created. It is strongly recommended that this value should be specified usingcoordinated universal time (UTC).Modification timeA 32-bit integer that specifies the calendar date and time (in seconds since midnight, January 1, 1904)when the movie atom was changed. BooleanIt is strongly recommended that this value should be specifiedusing coordinated universal time (UTC).Time scaleA time value that indicates the time scale for this movie—that is, the number of time units that pass persecond in its time coordinate system. A time coordinate system that measures time in sixtieths of a second,for example, has a time scale of 60.DurationA time value that indicates the duration of the movie in time scale units. Note that this property is derivedfrom the movie’s tracks. The value of this field corresponds to the duration of the longest track in themovie.Preferred rateA 32-bit fixed-point number that specifies the rate at which to play this movie. A value of 1.0 indicatesnormal rate.Preferred volumeA 16-bit fixed-point number that specifies how loud to play this movie’s sound. A value of 1.0 indicatesfull volume.ReservedTen bytes reserved for use by Apple. Set to 0.Matrix structureThe matrix structure associated with this movie. A matrix shows how to map points from one coordinatespace into another. See “Matrices” (page 320) for a discussion of how display matrices are used in QuickTime.Preview timeThe time value in the movie at which the preview begins.Preview durationThe duration of the movie preview in movie time scale units.Poster timeThe time value of the time of the movie poster.2012-08-14 | © 2004, 2012 Apple Inc. All Rights Reserved.45